DIMENSIONAL
ENGINEERING
Based on the ASME Y14.5M1994 Dimensioning and
Tolerancing Standard
INTRODUCTION
Geometric dimensioning and tolerancing (GD&T) is an
international engineering language that is used on
engineering drawings (blue prints) to describe product in
three dimensions. GD&T uses a series of internationally
recognized symbols rather than words to describe the
product. These symbols are applied to the features of a
part and provide a very concise and clear definition of
design intent.
GD&T is a very precise mathematical language that
describes the form, orientation and location of part
features in zones of tolerance. These zones of tolerance
are then described relative to a Cartesian coordinate
system.
ASME Y14.5M-1994
American national Standards Institute/American Society
of Mechanical Engineers
Tolerances
of Form
Straightness
(ASME Y14.5M-1994, 6.4.1)
Flatness
(ASME Y14.5M-1994, 6.4.2)
Circularity
(ASME Y14.5M-1994, 6.4.3)
Cylindricity
(ASME Y14.5M-1994, 6.4.4)
Extreme Variations of Form
Allowed By Size Tolerance
25.1
25
25
(MMC)
25.1
(LMC)
25.1
(LMC)
25
(MMC)
MMC Perfect
Form Boundary
25.1
(LMC)
Internal Feature of Size
Extreme Variations of Form
Allowed By Size Tolerance
25
24.9
24.9
(LMC)
25
(MMC)
24.9
(LMC)
MMC Perfect
Form Boundary
25
(MMC)
24.9
(LMC)
External Feature of Size
Straightness
(Flat Surfaces)
0.5
0.1
25 +/-0.25
0.1 Tolerance
0.5 Tolerance
Straightness is the condition where an element of a
surface or an axis is a straight line
Straightness
(Flat Surfaces)
0.5 Tolerance Zone
25.25 max
24.75 min
0.1 Tolerance Zone
In this example each line element of the surface must lie
within a tolerance zone defined by two parallel lines
separated by the specified tolerance value applied to each
view. All points on the surface must lie within the limits of
size and the applicable straightness limit.
The straightness tolerance is applied in the view where the
elements to be controlled are represented by a straight line
Straightness
(Surface Elements)
0.1
0.1 Tolerance Zone
MMC
0.1 Tolerance Zone
MMC
0.1 Tolerance Zone
MMC
In this example each longitudinal element of the surface must
lie within a tolerance zone defined by two parallel lines
separated by the specified tolerance value. The feature must
be within the limits of size and the boundary of perfect form at
MMC. Any barreling or waisting of the feature must not
exceed the size limits of the feature.
Straightness (RFS)
0.1
0.1 Diameter
Tolerance Zone
MMC
Outer Boundary (Max)
Outer Boundary = Actual Feature Size + Straightness Tolerance
In this example the derived median line of the feature’s actual local
size must lie within a tolerance zone defined by a cylinder whose
diameter is equal to the specified tolerance value regardless of the
feature size. Each circular element of the feature must be within
the specified limits of size. However, the boundary of perfect form
at MMC can be violated up to the maximum outer boundary or
virtual condition diameter.
Straightness (MMC)
15
14.85
0.1
15
(MMC)
M
0.1 Diameter
Tolerance Zone
15.1 Virtual Condition
14.85
(LMC)
0.25 Diameter
Tolerance Zone
15.1 Virtual Condition
Virtual Condition = MMC Feature Size + Straightness Tolerance
In this example the derived median line of the feature’s actual local size
must lie within a tolerance zone defined by a cylinder whose diameter is
equal to the specified tolerance value at MMC. As each circular element
of the feature departs from MMC, the diameter of the tolerance cylinder
is allowed to increase by an amount equal to the departure from the local
MMC size. Each circular element of the feature must be within the
specified limits of size. However, the boundary of perfect form at MMC
can be violated up to the virtual condition diameter.
Flatness
0.1
25 +/-0.25
0.1 Tolerance Zone
0.1 Tolerance Zone
24.75 min
25.25 max
In this example the entire surface must lie within a tolerance
zone defined by two parallel planes separated by the specified
tolerance value. All points on the surface must lie within the
limits of size and the flatness limit.
Flatness is the condition of a surface having all elements in
one plane. Flatness must fall within the limits of size. The
flatness tolerance must be less than the size tolerance.
Circularity
(Roundness)
0.1
90
0.1
90
0.1 Wide Tolerance Zone
In this example each circular element of the surface must lie within a
tolerance zone defined by two concentric circles separated by the
specified tolerance value. All points on the surface must lie within the
limits of size and the circularity limit.
Circularity is the condition of a surface where all points of the
surface intersected by any plane perpendicular to a common
axis are equidistant from that axis. The circularity tolerance
must be less than the size tolerance
Cylindricity
0.1
0.1 Tolerance Zone
MMC
In this example the entire surface must lie within a tolerance zone
defined by two concentric cylinders separated by the specified
tolerance value. All points on the surface must lie within the limits of
size and the cylindricity limit.
Cylindricity is the condition of a surface of revolution in which
all points are equidistant from a common axis. Cylindricity is a
composite control of form which includes circularity
(roundness), straightness, and taper of a cylindrical feature.
Form Control Quiz
Questions #1-5 Fill in blanks (choose from below)
1. The four form controls are ____________, ________,
___________, and ____________.
2. Rule #1 states that unless otherwise specified a feature of
size must have ____________at MMC.
3. ____________ and ___________ are individual line or circular
element (2-D) controls.
4. ________ and ____________are surface (3-D) controls.
5. Circularity can be applied to both ________and _______ cylindrical
parts.
straightness
straight
perfect form
cylindricity
angularity
flatness
tapered
profile
circularity
true position
Answer questions #6-10 True or False
6. Form controls require a datum reference.
7. Form controls do not directly control a feature’s size.
8. A feature’s form tolerance must be less than it’s size
tolerance.
9. Flatness controls the orientation of a feature.
10. Size limits implicitly control a feature’s form.
Tolerances of
Orientation
Angularity
(ASME Y14.5M-1994 ,6.6.2)
Perpendicularity
(ASME Y14.5M-1994 ,6.6.4)
Parallelism
(ASME Y14.5M-1994 ,6.6.3)
Angularity
(Feature Surface to Datum Surface)
20 +/-0.5
0.3 A
30
o
A
19.5 min
20.5 max
30
A
0.3 Wide
Tolerance
Zone
o
30
A
0.3 Wide
Tolerance
Zone
The tolerance zone in this example is defined
by two parallel planes oriented at the
specified angle to the datum reference plane.
Angularity is the condition of the planar feature surface at a
specified angle (other than 90 degrees) to the datum
reference plane, within the specified tolerance zone.
o
Angularity
(Feature Axis to Datum Surface)
NOTE: Tolerance applies
to feature at RFS
0.3 A
0.3 Circular
Tolerance Zone
0.3 Circular
Tolerance Zone
60 o
A
The tolerance zone in this example is defined by a
cylinder equal to the length of the feature, oriented
at the specified angle to the datum reference plane.
A
Angularity is the condition of the feature axis at a specified
angle (other than 90 degrees) to the datum reference plane,
within the specified tolerance zone.
Angularity
(Feature Axis to Datum Axis)
NOTE: Feature axis must lie
within tolerance zone cylinder
0.3 A
NOTE: Tolerance
applies to feature
at RFS
A
0.3 Circular
Tolerance Zone
0.3 Circular
Tolerance Zone
45 o
Datum Axis A
The tolerance zone in this example is defined by a
cylinder equal to the length of the feature, oriented
at the specified angle to the datum reference axis.
Angularity is the condition of the feature axis at a specified
angle (other than 90 degrees) to the datum reference axis,
within the specified tolerance zone.
Perpendicularity
(Feature Surface to Datum Surface)
0.3 A
A
0.3 Wide
Tolerance Zone
A
0.3 Wide Tolerance
Zone
The tolerance zone in this example is
defined by two parallel planes oriented
perpendicular to the datum reference
plane.
A
Perpendicularity is the condition of the planar feature
surface at a right angle to the datum reference plane, within
the specified tolerance zone.
Perpendicularity
(Feature Axis to Datum Surface)
0.3 Diameter
Tolerance Zone
NOTE: Tolerance applies
to feature at RFS
0.3 Circular
Tolerance Zone
C
0.3 Circular
Tolerance Zone
0.3 C
The tolerance zone in this example is
defined by a cylinder equal to the length of
the feature, oriented perpendicular to the
datum reference plane.
Perpendicularity is the condition of the feature axis at a right
angle to the datum reference plane, within the specified
tolerance zone.
Perpendicularity
(Feature Axis to Datum Axis)
NOTE: Tolerance applies
to feature at RFS
0.3 A
A
0.3 Wide Tolerance
Zone
Datum Axis A
The tolerance zone in this example is
defined by two parallel planes oriented
perpendicular to the datum reference axis.
Perpendicularity is the condition of the feature axis at a right
angle to the datum reference axis, within the specified
tolerance zone.
Parallelism
(Feature Surface to Datum Surface)
0.3 A
25 +/-0.5
A
0.3 Wide Tolerance Zone
25.5 max
0.3 Wide Tolerance Zone
24.5 min
A
The tolerance zone in this example
is defined by two parallel planes
oriented parallel to the datum
reference plane.
A
Parallelism is the condition of the planar feature surface
equidistant at all points from the datum reference plane,
within the specified tolerance zone.
Parallelism
(Feature Axis to Datum Surface)
NOTE: The specified tolerance
does not apply to the orientation
of the feature axis in this direction
NOTE: Tolerance applies
to feature at RFS
0.3 Wide Tolerance
Zone
0.3 A
A
The tolerance zone in this example
is defined by two parallel planes
oriented parallel to the datum
reference plane.
A
Parallelism is the condition of the feature axis equidistant
along its length from the datum reference plane, within the
specified tolerance zone.
Parallelism
(Feature Axis to Datum Surfaces)
0.3 Circular
Tolerance Zone
B
NOTE: Tolerance applies
to feature at RFS
0.3 Circular
Tolerance Zone
0.3 Circular
Tolerance Zone
0.3 A B
B
A
The tolerance zone in this example is
defined by a cylinder equal to the
length of the feature, oriented parallel
to the datum reference planes.
A
Parallelism is the condition of the feature axis equidistant
along its length from the two datum reference planes, within
the specified tolerance zone.
Parallelism
(Feature Axis to Datum Axis)
The tolerance zone in this example is
defined by a cylinder equal to the
length of the feature, oriented
parallel to the datum reference axis.
NOTE: Tolerance applies
to feature at RFS
0.1 Circular
Tolerance Zone
0.1 A
A
0.1 Circular
Tolerance Zone
Datum Axis A
Parallelism is the condition of the feature axis equidistant along
its length from the datum reference axis, within the specified
tolerance zone.
Orientation Control Quiz
Questions #1-5 Fill in blanks (choose from below)
1. The three orientation controls are __________, ___________,
and ________________.
2. A _______________
is always required when applying any of
the orientation controls.
3. ________________
is the appropriate geometric tolerance when
controlling the orientation of a feature at right angles to a datum
reference.
4. Mathematically all three orientation tolerances are _________.
5. Orientation tolerances do not control the ________ of a feature.
perpendicularity
datum feature
angularity
datum target
location
identical
datum reference
parallelism
profile
Answer questions #6-10 True or False
6. Orientation tolerances indirectly control a feature’s form.
7. Orientation tolerance zones can be cylindrical.
8. To apply a perpendicularity tolerance the desired angle
must be indicated as a basic dimension.
9. Parallelism tolerances do not apply to features of size.
10. To apply an angularity tolerance the desired angle must
be indicated as a basic dimension.
Tolerances
of Runout
Circular Runout
(ASME Y14.5M-1994, 6.7.1.2.1)
Total Runout
(ASME Y14.5M-1994 ,6.7.1.2.2)
Features Applicable
to Runout Tolerancing
Internal surfaces
constructed around a
datum axis
External surfaces
constructed around
a datum axis
Datum axis (established
from datum feature
Datum feature
Angled surfaces
constructed around
a datum axis
Surfaces constructed
perpendicular to a
datum axis
Circular Runout
Total
Tolerance
Maximum
Circular runout can only be applied on an
RFS basis and cannot be modified to
MMC or LMC.
Minimum
Full Indicator
Movement
Maximum
Reading
+
Minimum
Reading
0
-
Measuring position #1
(circular element #1)
Full Part
Rotation
Measuring position #2
(circular element #2)
When measuring circular runout, the indicator must be reset to zero at each measuring position
along the feature surface. Each individual circular element of the surface is independently
allowed the full specified tolerance. In this example, circular runout can be used to detect 2dimensional wobble (orientation) and waviness (form), but not 3-dimensional characteristics
such as surface profile (overall form) or surface wobble (overall orientation).
Circular Runout
(Angled Surface to Datum Axis)
0.75 A
A
50 +/-0.25
50
o
+/- 2
o
As Shown
on Drawing
Means This:
Allowable indicator
reading = 0.75 max.
Full Indicator
Movement
(
)
-
0
+
The tolerance zone for any individual circular
element is equal to the total allowable movement
of a dial indicator fixed in a position normal to the
true geometric shape of the feature surface when
the part is rotated 360 degrees about the datum
axis. The tolerance limit is applied independently
to each individual measuring position along the
feature surface.
Collet or Chuck
When measuring circular
runout, the indicator must
be reset when repositioned
along the feature surface.
Datum axis A
360 o Part
Rotation
Single circular
element
NOTE: Circular runout in this example only
controls the 2-dimensional circular elements
(circularity and coaxiality) of the angled feature
surface not the entire angled feature surface
Circular Runout
(Surface Perpendicular to Datum Axis)
0.75 A
A
50 +/-0.25
As Shown
on Drawing
Means This:
Single circular
element
The tolerance zone for any individual circular
element is equal to the total allowable movement
of a dial indicator fixed in a position normal to the
true geometric shape of the feature surface when
the part is rotated 360 degrees about the datum
axis. The tolerance limit is applied independently
to each individual measuring position along the
feature surface.
-
360 o Part
Rotation
0
+
When measuring circular runout, the indicator must
be reset when repositioned along the feature surface.
Allowable indicator
reading = 0.75 max.
Datum axis A
NOTE: Circular runout in this example will
only control variation in the 2-dimensional
circular elements of the planar surface (wobble
and waviness) not the entire feature surface
Circular Runout
(Surface Coaxial to Datum Axis)
0.75 A
A
50 +/-0.25
As Shown
on Drawing
Means This:
The tolerance zone for any individual circular element is equal
to the total allowable movement of a dial indicator fixed in a
position normal to the true geometric shape of the feature
surface when the part is rotated 360 degrees about the datum
axis. The tolerance limit is applied independently to each
individual measuring position along the feature surface.
+
Allowable indicator
reading = 0.75 max.
0
-
When measuring circular runout,
the indicator must be reset when
repositioned along the feature
surface.
Single circular element
360 o Part
Rotation
Datum axis A
NOTE: Circular runout in this example will
only control variation in the 2-dimensional
circular elements of the surface (circularity and
coaxiality) not the entire feature surface
Circular Runout
(Surface Coaxial to Datum Axis)
0.75 A-B
A
B
As Shown
on Drawing
Means This:
The tolerance zone for any individual circular element is equal
to the total allowable movement of a dial indicator fixed in a
position normal to the true geometric shape of the feature
surface when the part is rotated 360 degrees about the datum
axis. The tolerance limit is applied independently to each
individual measuring position along the feature surface.
+
Allowable indicator
reading = 0.75 max.
Machine
center
0
-
When measuring circular runout,
the indicator must be reset when
repositioned along the feature
surface.
Single circular element
Datum axis A-B
360 o Part
Rotation
Machine
center
NOTE: Circular runout in this example will
only control variation in the 2-dimensional
circular elements of the surface (circularity and
coaxiality) not the entire feature surface
Circular Runout
(Surface Related to Datum Surface and Axis)
A
B
0.75 A B
50 +/-0.25
As Shown
on Drawing
The tolerance zone for any individual circular element is
equal to the total allowable movement of a dial indicator fixed
in a position normal to the true geometric shape of the
feature surface when the part is located against the datum
surface and rotated 360 degrees about the datum axis. The
tolerance limit is applied independently to each individual
measuring position along the feature surface.
Means This:
Single circular element
Allowable indicator
reading = 0.75 max.
Stop collar
360 o Part
Rotation
+
0
-
Collet or Chuck
Datum axis B
When measuring circular runout,
the indicator must be reset when
repositioned along the feature
surface.
Datum plane A
Total Runout
Total
Tolerance
Maximum
Total runout can only be applied on an
RFS basis and cannot be modified to
MMC or LMC.
Minimum
Full Indicator
Movement
Maximum
Reading
Minimum
Reading
+
0
-
Indicator
Path
Full Part
Rotation
+
0
-
When measuring total runout, the indicator is moved in a straight line along the feature surface
while the part is rotated about the datum axis. It is also acceptable to measure total runout by
evaluating an appropriate number of individual circular elements along the surface while the part
is rotated about the datum axis. Because the tolerance value is applied to the entire surface, the
indicator must not be reset to zero when moved to each measuring position. In this example,
total runout can be used to measure surface profile (overall form) and surface wobble (overall
orientation).
Total Runout
(Angled Surface to Datum Axis)
0.75 A
A
50 +/-0.25
50
o
+/- 2
o
As Shown
on Drawing
Means This:
When measuring total runout, the
indicator must not be reset when
repositioned along the feature
surface.
-
0
+
0
+
The tolerance zone for the entire angled surface is
equal to the total allowable movement of a dial
indicator positioned normal to the true geometric
shape of the feature surface when the part is
rotated about the datum axis and the indicator is
moved along the entire length of the feature
surface.
Allowable indicator reading = 0.75 max.
(applies to the entire feature surface)
Collet or Chuck
Full Part
Rotation
Datum axis A
NOTE: Unlike circular runout, the use of total runout
will provide 3-dimensional composite control of the
cumulative variations of circularity, coaxiality,
angularity, taper and profile of the angled surface
Total Runout
(Surface Perpendicular to Datum Axis)
0.75 A
10
35
50 +/-0.25
A
Means This:
10
35
Full Part
Rotation
As Shown
on Drawing
The tolerance zone for the portion of the feature surface
indicated is equal to the total allowable movement of a dial
indicator positioned normal to the true geometric shape of the
feature surface when the part is rotated about the datum axis
and the indicator is moved along the portion of the feature
surface within the area described by the basic dimensions.
-
0
-
0
+
+
When measuring total runout, the indicator
must not be reset when repositioned along the
feature surface.
Allowable indicator reading = 0.75 max.
(applies to portion of feature surface indicated)
Datum axis A
NOTE: The use of total runout in this example
will provide composite control of the cumulative
variations of perpendicularity (wobble) and
flatness (concavity or convexity) of the feature
surface.
Runout Control Quiz
Answer questions #1-12 True or False
1. Total runout is a 2-dimensional
control.
2. Runout tolerances are used on rotating parts.
3. Circular runout tolerances apply to single elements .
4. Total runout tolerances should be applied at MMC.
5. Runout tolerances can be applied to surfaces at right
angles to the datum reference.
6. Circular runout tolerances are used to control an entire
feature surface.
7. Runout tolerances always require a datum reference.
8. Circular runout and total runout both control axis to
surface relationships.
9. Circular runout can be applied to control taper of a part.
10. Total runout tolerances are an appropriate way to limit
“wobble” of a rotating surface.
11.
Runout tolerances are used to control a feature’s size.
12. Total runout can control circularity, straightness, taper,
coaxiality, angularity and any other surface variation.
Tolerances
of Profile
Profile of a Line
(ASME Y14.5M-1994, 6.5.2b)
Profile of a Surface
(ASME Y14.5M-1994, 6.5.2a)
Profile of a Line
20 X 20
A1
B
20 X 20
A3
20 X 20
A2
C
1 A B C
17 +/- 1
A
1 Wide Profile
Tolerance Zone
2 Wide Size
Tolerance Zone
18 Max
16 Min.
The profile tolerance zone in this example is defined by two
parallel lines oriented with respect to the datum reference
frame. The profile tolerance zone is free to float within the
larger size tolerance and applies only to the form and
orientation of any individual line element along the entire
surface.
Profile of a Line is a two-dimensional tolerance that can be applied to a
part feature in situations where the control of the entire feature surface as
a single entity is not required or desired. The tolerance applies to the line
element of the surface at each individual cross section indicated on the
drawing.
Profile of a Surface
20 X 20
A1
B
20 X 20
A3
20 X 20
A2
2 A B C
C
23.5
A
2 Wide Tolerance Zone
Size, Form and Orientation
23.5
Nominal
Location
The profile tolerance zone in this example is defined by two parallel
planes oriented with respect to the datum reference frame. The profile
tolerance zone is located and aligned in a way that enables the part
surface to vary equally about the true profile of the feature.
Profile of a Surface is a three-dimensional tolerance that can be applied
to a part feature in situations where the control of the entire feature
surface as a single entity is desired. The tolerance applies to the entire
surface and can be used to control size, location, form and/or orientation
of a feature surface.
Profile of a Surface
(Bilateral Tolerance)
20 X 20
A1
B
20 X 20
A3
20 X 20
A2
1 A B C
C
50
1 Wide Total
Tolerance Zone
B
0.5 Inboard
0.5 Outboard
C
50
Nominal Location
The tolerance zone in this example is defined by two parallel planes
oriented with respect to the datum reference frame. The profile tolerance
zone is located and aligned in a way that enables the part surface to
vary equally about the true profile of the trim.
Profile of a Surface when applied to trim edges of sheet metal parts will control
the location, form and orientation of the entire trimmed surface. When a
bilateral value is specified, the tolerance zone allows the trim edge variation
and/or locational error to be on both sides of the true profile. The tolerance
applies to the entire edge surface.
Profile of a Surface
(Unilateral Tolerance)
20 X 20
A1
B
20 X 20
A3
20 X 20
A2
0.5 A B C
C
50
0.5 Wide Total
Tolerance Zone
B
C
50
Nominal Location
The tolerance zone in this example is defined by two parallel planes
oriented with respect to the datum reference frame. The profile tolerance
zone is located and aligned in a way that allows the trim surface to vary
from the true profile only in the inboard direction.
Profile of a Surface when applied to trim edges of sheet metal parts will control
the location, form and orientation of the entire trimmed surface. When a
unilateral value is specified, the tolerance zone limits the trim edge variation
and/or locational error to one side of the true profile. The tolerance applies to
the entire edge surface.
Profile of a Surface
(Unequal Bilateral Tolerance)
20 X 20
A1
B
20 X 20
A3
20 X 20
A2
0.5
1.2 A B C
C
50
1.2 Wide Total
Tolerance Zone
B
0.5 Inboard
0.7 Outboard
C
50
Nominal Location
The tolerance zone in this example is defined by two parallel planes
oriented with respect to the datum reference frame. The profile tolerance
zone is located and aligned in a way that enables the part surface to
vary from the true profile more in one direction (outboard) than in the
other (inboard).
Profile of a Surface when applied to trim edges of sheet metal parts will control
the location, form and orientation of the entire trimmed surface. Typically when
unequal values are specified, the tolerance zone will represent the actual
measured trim edge variation and/or locational error. The tolerance applies to
the entire edge surface.
Profile of a Surface
0.5 A
0.1
Location &
Orientation
Form Only
25
A
0.1 Wide Tolerance Zone
25.25
24.75
A
Composite Profile of Two Coplanar
Surfaces w/o Orientation Refinement
Profile of a Surface
0.5 A
0.1 A
Location
Form & Orientation
25
A
0.1 Wide Tolerance Zone
25.25
A
0.1 Wide Tolerance Zone
24.75
A
Composite Profile of Two Coplanar
Surfaces With Orientation Refinement
Profile Control Quiz
Answer questions #1-13 True or False
1. Profile tolerances always require a datum reference.
2. Profile of a surface tolerance is a 2-dimensional control.
3. Profile of a surface tolerance should be used to control
trim edges on sheet metal parts.
4. Profile of a line tolerances should be applied at MMC.
5. Profile tolerances can be applied to features of size.
6. Profile tolerances can be combined with other geometric
controls such as flatness to control a feature.
7. Profile of a line tolerances apply to an entire surface.
8. Profile of a line controls apply to individual line elements.
9. Profile tolerances only control the location of a surface.
10. Composite profile controls should be avoided because
they are more restrictive and very difficult to check.
11.
Profile tolerances can be applied either bilateral or
unilateral to a feature.
12. Profile tolerances can be applied in both freestate and
restrained datum conditions.
13. Tolerances shown in the lower segment of a composite
profile feature control frame control the location of a
feature to the specified datums.
Profile Control Quiz
Questions #1-9 Fill in blanks (choose from below)
1. The two types of profile tolerances are _________________,
and ____________________.
2. Profile tolerances can be used to control the ________, ____,
___________ , and sometimes size of a feature.
3. Profile tolerances can be applied _________ or __________.
4. _________________ tolerances are 2-dimensional controls.
5. ____________________
tolerances are 3-dimensional controls.
6. _________________ can be used when different tolerances are
required for location and form and/or orientation.
7. When using profile tolerances to control the location and/or orientation of
a feature, a _______________ must be included
in the feature control frame.
8. When using profile tolerances to control form only, a ______
__________ is not required in the feature control frame.
9. In composite profile applications, the tolerance shown in the upper
segment of the feature control frame applies only to the ________ of
the feature.
composite profile
bilateral
virtual condition
profile of a surface
primary datum orientation
datum reference
unilateral
profile of a line
location
true geometric counterpart
form
Tolerances
of Location
True Position
(ASME Y14.5M-1994, 5.2)
Concentricity
(ASME Y14.5M-1994, 5.12)
Symmetry
(ASME Y14.5M-1994, 5.13)
Notes
Coordinate vs Geometric
Tolerancing Methods
8.5 +/- 0.1
1.4 A B C
8.5 +/- 0.1
Circular Tolerance
Zone
Rectangular
Tolerance Zone
10.25 +/- 0.5
10.25
B
10.25 +/- 0.5
10.25
C
A
Coordinate Dimensioning
Geometric Dimensioning
+/- 0.5
1.4
+/- 0.5
Rectangular Tolerance Zone
57% Larger
Tolerance Zone
Circular Tolerance Zone
Circular Tolerance Zone
Rectangular Tolerance Zone
Increased Effective Tolerance
Positional Tolerance Verification
(Applies when a circular tolerance is indicated)
X
Z
Feature axis actual
location (measured)
Y
Positional
tolerance zone
cylinder
Actual feature
boundary
Feature axis true
position (designed)
Formula to determine the actual radial
position of a feature using measured
coordinate values (RFS)
Z=
Z
X2 + Y2
positional tolerance /2
Z = total radial deviation
X2 = “X” measured deviation
Y2 = “Y” measured deviation
Positional Tolerance Verification
(Applies when a circular tolerance is indicated)
X
Z
Feature axis actual
location (measured)
Y
Positional
tolerance zone
cylinder
Actual feature
boundary
Feature axis true
position (designed)
Formula to determine the actual radial
position of a feature using measured
coordinate values (MMC)
X2 + Y2
+( actual - MMC)
Z
2
= positional tolerance
Z = total radial deviation
X2 = “X” measured deviation
Y2 = “Y” measured deviation
Z =
Bi-directional True Position
Rectangular Coordinate Method
1.5 A B C
2X
2X
0.5 A B C
C
A
10
B
10
As Shown
on Drawing
35
2X
6 +/-0.25
Means This:
True Position Related
to Datum Reference Frame
1.5 Wide
Tolerance
Zone
C
10
B
10
35
0.5 Wide
Tolerance Zone
Each axis must lie within the 1.5 X 0.5 rectangular tolerance zone
basically located to the datum reference frame
Bi-directional True Position
Multiple Single-Segment Method
2X
6 +/-0.25
1.5 A B C
0.5 A B
C
A
10
B
10
As Shown
on Drawing
35
Means This:
True Position Related
to Datum Reference Frame
1.5 Wide
Tolerance
Zone
C
10
B
10
35
0.5 Wide
Tolerance Zone
Each axis must lie within the 1.5 X 0.5 rectangular tolerance zone
basically located to the datum reference frame
Bi-directional True Position
Noncylndrical Features (Boundary Concept)
2X 13 +/-0.25
1.5 M A B C
BOUNDARY
2X 6 +/-0.25
0.5 M A B C
BOUNDARY
C
A
10
B
10
35
As Shown
on Drawing
5.75 MMC length of slot
-0.50 Position tolerance
5.25 maximum boundary
Means This:
Both holes must be within the size limits and no
portion of their surfaces may lie within the area
described by the 11.25 x 5.25 maximum
boundaries when the part is positioned with
respect to the datum reference frame. The
boundary concept can only be applied on an
MMC basis.
12.75 MMC width of slot
-1.50 Position tolerance
11.25 Maximum boundary
True position boundary related
to datum reference frame
C
90 o
10
10
35
B
A
Composite True Position
Without Pattern Orientation Control
2X
6 +/-0.25
1.5 A B C
0.5 A
C
A
10
B
10
35
As Shown
on Drawing
Means This:
1.5 Pattern-Locating
Tolerance Zone Cylinder
0.5 Feature-Relating
Tolerance Zone Cylinder
pattern location relative
to Datums A, B, and C
pattern orientation relative to
Datum A only (perpendicularity)
C
10
B
10
35
True Position Related
to Datum Reference
Frame
Each axis must lie within each tolerance zone simultaneously
Composite True Position
With Pattern Orientation Control
2X
6 +/-0.25
1.5 A B C
0.5 A B
C
A
10
B
10
35
As Shown
on Drawing
Means This:
1.5 Pattern-Locating
Tolerance Zone Cylinder
True Position Related
to Datum Reference
Frame
pattern location relative
to Datums A, B, and C
C
10
B
10
35
0.5 Feature-Relating
Tolerance Zone Cylinder
pattern orientation relative to
Datums A and B
Each axis must lie within each tolerance zone simultaneously
Location (Concentricity)
Datum Features at RFS
6.35 +/- 0.05
0.5 A
A
15.95
15.90
As Shown on Drawing
Means This:
Axis of Datum
Feature A
0.5 Coaxial
Tolerance Zone
Derived Median Points of
Diametrically Opposed Elements
Within the limits of size and regardless of feature size, all median points of
diametrically opposed elements must lie within a
0.5 cylindrical
tolerance zone. The axis of the tolerance zone coincides with the axis of
datum feature A. Concentricity can only be applied on an RFS basis.
Location (Symmetry)
Datum Features at RFS
6.35 +/- 0.05
0.5 A
A
15.95
15.90
As Shown on Drawing
Means This:
Center Plane of
Datum Feature A
0.5 Wide
Tolerance Zone
Derived Median
Points
Within the limits of size and regardless of feature size, all median points
of opposed elements must lie between two parallel planes equally
disposed about datum plane A, 0.5 apart. Symmetry can only be
applied on an RFS basis.
True Position Quiz
Answer questions #1-11 True or False
1. Positional tolerances are applied to individual or patterns
of features of size.
2. Cylindrical tolerance zones more closely represent the
functional requirements of a pattern of clearance holes.
3. True position tolerance values are used to calculate the
minimum size of a feature required for assembly.
4. True position tolerances can control a feature’s size.
5. Positional tolerances are applied on an MMC, LMC, or
RFS basis.
6. Composite true position tolerances should be avoided
because it is overly restrictive and difficult to check.
7. Composite true position tolerances can only be applied
to patterns of related features.
8. The tolerance value shown in the upper segment of a
composite true position feature control frame applies
to the location of a pattern of features to the specified
datums.
9. The tolerance value shown in the lower segment of a
composite true position feature control frame applies
to the location of a pattern of features to the specified
datums.
10. Positional tolerances can be used to control circularity
11.
True position tolerances can be used to control center
distance relationships between features of size.
True Position Quiz
Questions #1-9 Fill in blanks (choose from below)
1. Positional tolerance zones can be ___________, ___________,
or spherical
2. ________________
are used to establish the true (theoretically
exact) position of a feature from specified datums.
3. Positional tolerancing is a _____________
control.
4. Positional tolerance can apply to the ____ or ________________
a feature.
5. _____ and ________ fastener equations are used to determine
appropriate clearance hole sizes for mating details
6. _________ tolerance zones are recommended to prevent fastener
interference in mating details.
7. The tolerance shown in the upper segment of a composite true
position feature control frame is called the ________________
tolerance zone.
8. The tolerance shown in the lower segment of a composite true
position feature control frame is called the ________________
tolerance zone.
9. Functional gaging principles can be applied when __________
________ condition is specified
surface boundary
floating
feature-relating
pattern-locating
rectangular
cylindrical
3-dimensional
basic dimensions
projected
location
maximum material
fixed
axis
of
Notes
Notes
Fixed and
Floating
Fastener
Exercises
Floating Fasteners
In applications where two or more mating details are assembled, and all parts
have clearance holes for the fasteners, the floating fastener formula shown
below can be used to calculate the appropriate hole sizes or positional tolerance
requirements to ensure assembly. The formula will provide a “zero-interference” fit
when the features are at MMC and at their extreme of positional tolerance
2x M10 X 1.5
(Reference)
H=F+T or T=H-F
A
B
2x
General Equation Applies to
Each Part Individually
H= Min. diameter of clearance hole
F= Maximum diameter of fastener
T= Positional tolerance diameter
10.50 +/- 0.25
?.? M
Calculate Required
Positional Tolerance
T=H-F
H = Minimum Hole Size =
F = Max. Fastener Size =
T = 10.25 -10
T = ______
A
2x
Calculate
Nominal Size
??.?? +/- 0.25
0.5 M
remember: the size tolerance must be
added to the calculated MMC hole size to
obtain the correct nominal value.
H = F +T
F = Max. Fastener Size =
T = Positional Tolerance =
B
10.25
10
H = 10 + 0.50
H = ______
10
0.50
Floating Fasteners
In applications where two or more mating details are assembled, and all parts
have clearance holes for the fasteners, the floating fastener formula shown
below can be used to calculate the appropriate hole sizes or positional tolerance
requirements to ensure assembly. The formula will provide a “zero-interference” fit
when the features are at MMC and at their extreme of positional tolerance
2x M10 X 1.5
(Reference)
H=F+T or T=H-F
A
B
2x
General Equation Applies to
Each Part Individually
H= Min. diameter of clearance hole
F= Maximum diameter of fastener
T= Positional tolerance diameter
10.50 +/- 0.25
0.25 M
Calculate Required
Positional Tolerance
T=H-F
H = Minimum Hole Size =
F = Max. Fastener Size =
T = 10.25 -10
T = 0.25
A
2x
Calculate
Nominal Size
10.75 +/- 0.25
0.5 M
remember: the size tolerance must be
added to the calculated MMC hole size to
obtain the correct nominal value.
H = F +T
F = Max. Fastener Size =
T = Positional Tolerance =
B
10.25
10
H=
H=
10
0.5
10 + .5
10.5 Minimum
REMEMBER!!! All Calculations Apply at MMC
Fixed Fasteners
In fixed fastener applications where two mating details have equal positional
tolerances, the fixed fastener formula shown below can be used to calculate the
appropriate minimum clearance hole size and/or positional tolerance required to
ensure assembly. The formula provides a “zero-interference” fit when the features
are at MMC and at their extreme of positional tolerance. (Note that in this example
the positional tolerances indicated are the same for both parts.)
APPLIES WHEN A PROJECTED TOLERANCE ZONE IS USED
2x M10 X 1.5
(Reference)
General Equation Used When
Positional Tolerances Are Equal
10
A
H=F+2T or T=(H-F)/2
B
H= Min. diameter of clearance hole
F= Maximum diameter of fastener
T= Positional tolerance diameter
Calculate Required
Clearance Hole Size.
2x
+/- 0.25
??.??
0.8 M
A
H = F + 2T
Nominal Size
(MMC For Calculations)
2X M10 X 1.5
0.8 M P 10
remember: the size tolerance
must be added to the calculated
MMC size to obtain the correct
nominal value.
F = Max. Fastener Size =
T = Positional Tolerance =
H = 10.00 + 2(0.8)
H = _____
B
10.00
0.80
Fixed Fasteners
In fixed fastener applications where two mating details have equal positional
tolerances, the fixed fastener formula shown below can be used to calculate the
appropriate minimum clearance hole size and/or positional tolerance required to
ensure assembly. The formula provides a “zero-interference” fit when the features
are at MMC and at their extreme of positional tolerance. (Note that in this example
the positional tolerances indicated are the same for both parts.)
APPLIES WHEN A PROJECTED TOLERANCE ZONE IS USED
2x M10 X 1.5
(Reference)
General Equation Used When
Positional Tolerances Are Equal
10
A
H=F+2T or T=(H-F)/2
B
H= Min. diameter of clearance hole
F= Maximum diameter of fastener
T= Positional tolerance diameter
Calculate Required
Clearance Hole Size.
2x
11.85
0.8
+/- 0.25
M
A
H = F + 2T
Nominal Size
(MMC For Calculations)
2X M10 X 1.5
0.8 M P 10
remember: the size tolerance
must be added to the calculated
MMC size to obtain the correct
nominal value.
F = Max. Fastener Size =
T = Positional Tolerance =
10.00
0.80
H = 10.00 + 2(0.8)
H = 11.60 Minimum
B
REMEMBER!!! All Calculations Apply at MMC
Fixed Fasteners
In fixed fastener applications where two mating details have equal positional
tolerances, the fixed fastener formula shown below can be used to calculate the
appropriate minimum clearance hole size and/or positional tolerance required to
ensure assembly. The formula provides a “zero-interference” fit when the features
are at MMC and at their extreme of positional tolerance. (Note that in this example
the positional tolerances indicated are the same for both parts.)
APPLIES WHEN A PROJECTED TOLERANCE ZONE IS USED
2x M10 X 1.5
(Reference)
General Equation Used When
Positional Tolerances Are Equal
10
A
H=F+2T or T=(H-F)/2
B
H= Min. diameter of clearance hole
F= Maximum diameter of fastener
T= Positional tolerance diameter
Calculate Required
Clearance Hole Size.
2x
11.85
0.8
+/- 0.25
M
A
H = F + 2T
Nominal Size
(MMC For Calculations)
2X M10 X 1.5
0.8 M P 10
remember: the size tolerance
must be added to the calculated
MMC size to obtain the correct
nominal value.
F = Max. Fastener Size =
T = Positional Tolerance =
H = 10 + 2(0.8)
H = 11.6 Minimum
B
REMEMBER!!! All Calculations Apply at MMC
10
0.8
Fixed Fasteners
In applications where two mating details are assembled, and one part has
restrained fasteners, the fixed fastener formula shown below can be used to
calculate appropriate hole sizes and/or positional tolerances required to ensure
assembly. The formula will provide a “zero-interference” fit when the features are
at MMC and at their extreme of positional tolerance. (Note: in this example the
resultant positional tolerance is applied to both parts equally.)
APPLIES WHEN A PROJECTED TOLERANCE ZONE IS USED
2x M10 X 1.5
(Reference)
General Equation Used When
Positional Tolerances Are Equal
10
A
H=F+2T or T=(H-F)/2
B
H= Min. diameter of clearance hole
F= Maximum diameter of fastener
T= Positional tolerance diameter
2x
11.25 +/- 0.25
0.5 M
A
T = (H - F)/2
2X M10 X 1.5
0.5 M P 10
Nominal Size
(MMC For Calculations)
Calculate Required
Positional Tolerance .
(Both Parts)
H = Minimum Hole Size =
F = Max. Fastener Size =
T = (11 - 10)/2
T = 0.50
B
REMEMBER!!! All Calculations Apply at MMC
11
10
Fixed Fasteners
In fixed fastener applications where two mating details have unequal positional
tolerances, the fixed fastener formula shown below can be used to calculate the
appropriate minimum clearance hole size and/or positional tolerances required to
ensure assembly. The formula provides a “zero-interference” fit when the features
are at MMC and at their extreme of positional tolerance. (Note that in this example
the positional tolerances indicated are not equal.)
APPLIES WHEN A PROJECTED TOLERANCE ZONE IS USED
2x M10 X 1.5
General Equation Used When
Positional Tolerances Are Not Equal
(Reference)
10
H=F+(T1 + T2)
A
H = Min. diameter of clearance hole
F = Maximum diameter of fastener
T1= Positional tolerance (Part A) T2=
Positional tolerance (Part B)
B
Calculate Required
Clearance Hole Size.
2x
+/- 0.25
??.??
0.5 M
A
2X M10 X 1.5
1 M P 10
Nominal Size
(MMC For Calculations)
remember: the size tolerance must be
added to the calculated MMC hole size to
obtain the correct nominal value.
H=F+(T1 + T2)
F = Max. Fastener Size =
T1 = Positional Tol. (A) =
T2 = Positional Tol. (B) =
H = 10+ (0.5 + 1)
H = ____
B
10
0.50
1
Fixed Fasteners
In fixed fastener applications where two mating details have unequal positional
tolerances, the fixed fastener formula shown below can be used to calculate the
appropriate minimum clearance hole size and/or positional tolerances required to
ensure assembly. The formula provides a “zero-interference” fit when the features
are at MMC and at their extreme of positional tolerance. (Note that in this example
the positional tolerances indicated are not equal.)
APPLIES WHEN A PROJECTED TOLERANCE ZONE IS USED
2x M10 X 1.5
General Equation Used When
Positional Tolerances Are Not Equal
(Reference)
H= F+(T1 + T2)
A
10
H = Min. diameter of clearance hole
F = Maximum diameter of fastener
T1= Positional tolerance (Part A) T2=
Positional tolerance (Part B)
B
Calculate Required
Clearance Hole Size.
2x
+/- 0.25
11.75
0.5 M
A
2X M10 X 1.5
1 M P 10
Nominal Size
(MMC For Calculations)
remember: the size tolerance must be
added to the calculated MMC hole size to
obtain the correct nominal value.
H=F+(T1 + T2)
F = Max. Fastener Size =
T1 = Positional Tol. (A) =
T2 = Positional Tol. (B) =
H = 10 + (0.5 + 1)
H = 11.5 Minimum
B
REMEMBER!!! All Calculations Apply at MMC
10
0.5
1
Fixed Fasteners
In applications where a projected tolerance zone is not indicated, it is
necessary to select a positional tolerance and minimum clearance hole size
combination that will allow for any out-of-squareness of the feature containing the
fastener. The modified fixed fastener formula shown below can be used to
calculate the appropriate minimum clearance hole size required to ensure
assembly. The formula provides a “zero-interference” fit when the features are at
MMC and at the extreme positional tolerance.
APPLIES WHEN A PROJECTED TOLERANCE ZONE IS NOT USED
H
F
P
A
D
B
Calculate
Nominal Size
2x
H= Min. diameter of clearance hole
F= Maximum diameter of pin
T1= Positional tolerance (Part A)
T2= Positional tolerance (Part B)
D= Min. depth of pin (Part A)
P= Maximum projection of pin
??.?? +/-0.25
0.5 M
A
2x
remember: the size tolerance must be
added to the calculated MMC hole size to
obtain the correct nominal value.
H= F + T1 + T2 (1+(2P/D))
10.05 +/-0.05
0.5 M
F = Max. pin size
T1 = Positional Tol. (A)
T2 = Positional Tol. (B)
= Min. pin depth
= Max. pin projection
=
10
=
0.5
=
0.5 D
= 20. P
= 15
B
H = 10.00 + 0.5 + 0.5(1 + 2(15/20))
H=
__________
Fixed Fasteners
In applications where a projected tolerance zone is not indicated, it is
necessary to select a positional tolerance and minimum clearance hole size
combination that will allow for any out-of-squareness of the feature containing the
fastener. The modified fixed fastener formula shown below can be used to
calculate the appropriate minimum clearance hole size required to ensure
assembly. The formula provides a “zero-interference” fit when the features are at
MMC and at the extreme positional tolerance.
APPLIES WHEN A PROJECTED TOLERANCE ZONE IS NOT USED
H
F
P
A
D
B
Calculate
Nominal Size
2x
H= Min. diameter of clearance hole
F= Maximum diameter of pin
T1= Positional tolerance (Part A)
T2= Positional tolerance (Part B)
D= Min. depth of pin (Part A)
P= Maximum projection of pin
12 +/-0.25
0.5 M
A
2x
H= F + T1 + T2 (1+(2P/D))
remember: the size tolerance must be
added to the calculated MMC hole size to
obtain the correct nominal value.
H= F + T1 + T2 (1+(2P/D))
10.05 +/-0.05
0.5 M
F = Max. pin size
= 10
T1 = Positional tol. (A)
=
0.5
T2 = Positional tol. (B)
=
0.5 D
= Min. pin depth
=
20 P
= Max. pin projection =
15
B
H = 10 + 0.5 + 0.5(1 + 2(15/20))
H=
11.75 Minimum
REMEMBER!!! All Calculations Apply at MMC
Answers to Quizzes
and Exercises
Rules and Definitions Quiz
Questions #1-12 True or False
1.
Tight tolerances ensure high quality and performance.
FALSE
2.
The use of GD&T improves productivity.
TRUE
3.
Size tolerances control both orientation and position.
FALSE
4.
Unless otherwise specified size tolerances control form.
TRUE
5.
A material modifier symbol is not required for RFS.
TRUE
6.
A material modifier symbol is not required for MMC.
FALSE
7.
Title block default tolerances apply to basic dimensions.
FALSE
8.
A surface on a part is considered a feature.
TRUE
9.
Bilateral tolerances allow variation in two directions.
TRUE
10.
A free state modifier can only be applied to a tolerance.
FALSE
11.
A free state datum modifier applies to “assists” & “rests”.
TRUE
12.
Virtual condition applies regardless of feature size.
FALSE
Material Condition Quiz
Fill in blanks
Internal Features
MMC
LMC
10.75
11
23.45 +0.05/-0.25
23.2
23.5
123. 5 +/-0.1
123.4
123.6
.890
.895
10.75 +0.25/-0
.895
.890
External Features
MMC
10.75 +0/-0.25
10.75
10.5
23.5
23.2
23.45 +0.05/-0.25
123. 5 +/-0.1
.890
.885
LMC
123.6
123.4
.890
.885
Calculate appropriate values
Datum Quiz
Questions #1-12 True or False
1.
Datum target areas are theoretically exact.
FALSE
2.
Datum features are imaginary.
FALSE
3.
Primary datums have only three points of contact.
FALSE
4.
The 6 Degrees of Freedom are U/D, F/A, & C/C.
FALSE
5.
Datum simulators are part of the gage or tool.
TRUE
6.
Datum simulators are used to represent datums.
TRUE
7.
Datums are actual part features.
FALSE
8.
All datum features must be dimensionally stable.
TRUE
9.
Datum planes constrain degrees of freedom.
TRUE
10.
Tertiary datums are not always required.
TRUE
11.
All tooling locators (CD’s) are used as datums.
FALSE
12.
Datums should represent functional features.
TRUE
Datum Quiz
Questions #1-10 Fill in blanks (choose from below)
1. The three planes that make up a basic datum reference
frame are called primary, secondary, and tertiary.
2. An unrestrained part will exhibit 3-linear and 3-rotational degrees
of freedom.
3. A planar primary datum plane will restrain 1-linear and 2-rotational
degrees of freedom.
4. The primary and secondary datum planes together will restrain five degrees
of freedom.
5. The primary, secondary and tertiary datum planes together will
restrain all six degrees of freedom.
6. The purpose of a datum reference frame is to restrain movement
of a part in a gage or tool.
7. A datum must be functional, repeatable, and coordinated.
8. A datum feature is an actual feature on a part.
9. A datum is a theoretically exact point, axis or plane.
10. A datum simulator is a precise surface used to establish a
simulated datum.
restrain movement five coordinated repeatable
tertiary two 3-rotational primary 2-rotational
three functional one datum simulator 1-linear
datum feature datum secondary 3-linear
six
Form Control Quiz
Questions #1-5 Fill in blanks (choose from below)
1. The four form controls are straightness, flatness,
circularity, and cylindricity.
2. Rule #1 states that unless otherwise specified a feature of
size must have perfect form at MMC.
3. Straightness and circularity are individual line or circular
element (2-D) controls.
4. Flatness and cylindricity are surface (3-D) controls.
5. Circularity can be applied to both straight and tapered cylindrical
parts.
straightness
straight
perfect form
cylindricity
angularity
flatness
tapered
profile
circularity
true position
Answer questions #6-10 True or False
6. Form controls require a datum reference.
FALSE
7. Form controls do not directly control a feature’s size.
TRUE
8. A feature’s form tolerance must be less than it’s size
TRUE
tolerance.
9. Flatness controls the orientation of a feature.
10. Size limits implicitly control a feature’s form.
FALSE
TRUE
Orientation Control Quiz
Questions #1-5 Fill in blanks (choose from below)
1. The three orientation controls are angularity, parallelism,
and perpendicularity.
2. A datum reference is always required when applying any of
the orientation controls.
3. Perpendicularity is the appropriate geometric tolerance when
controlling the orientation of a feature at right angles to a datum
reference.
4. Mathematically all three orientation tolerances are identical.
5. Orientation tolerances do not control the location of a feature.
perpendicularity
datum feature
angularity
datum target
location
identical
datum reference
parallelism
profile
Answer questions #6-10 True or False
6. Orientation tolerances indirectly control a feature’s form.
TRUE
7. Orientation tolerance zones can be cylindrical.
TRUE
8. To apply a perpendicularity tolerance the desired angle
FALSE
must be indicated as a basic dimension.
9. Parallelism tolerances do not apply to features of size.
FALSE
10. To apply an angularity tolerance the desired angle must
TRUE
be indicated as a basic dimension.
Runout Control Quiz
Answer questions #1-12 True or False
1. Total runout is a 2-dimensional
control.
FALSE
2. Runout tolerances are used on rotating parts.
TRUE
3. Circular runout tolerances apply to single elements .
TRUE
4. Total runout tolerances should be applied at MMC.
FALSE
5. Runout tolerances can be applied to surfaces at right
TRUE
angles to the datum reference.
6. Circular runout tolerances are used to control an entire
FALSE
feature surface.
7. Runout tolerances always require a datum reference.
TRUE
8. Circular runout and total runout both control axis to
TRUE
surface relationships.
9. Circular runout can be applied to control taper of a part.
10. Total runout tolerances are an appropriate way to limit
FALSE
TRUE
“wobble” of a rotating surface.
11.
Runout tolerances are used to control a feature’s size.
12. Total runout can control circularity, straightness, taper,
coaxiality, angularity and any other surface variation.
FALSE
TRUE
Profile Control Quiz
Questions #1-9 Fill in blanks (choose from below)
1. The two types of profile tolerances are profile of a line, and
profile of a surface.
2. Profile tolerances can be used to control the location, form,
orientation, and sometimes size of a feature.
3. Profile tolerances can be applied bilateral or unilateral.
4. Profile of a line tolerances are 2-dimensional controls.
5. Profile of a surface tolerances are 3-dimensional controls.
6. Composite Profile can be used when different tolerances are
required for location and form and/or orientation.
7. When using profile tolerances to control the location and/or orientation of
a feature, a datum reference must be included in the feature control
frame.
8. When using profile tolerances to control form only, a datum
reference is not required in the feature control frame.
9. In composite profile applications, the tolerance shown in the upper
segment of the feature control frame applies only to the location of the
feature.
composite profile
bilateral
virtual condition
profile of a surface
primary datum orientation
datum reference
unilateral
profile of a line
location
true geometric counterpart
form
Profile Control Quiz
Answer questions #1-13 True or False
1. Profile tolerances always require a datum reference.
FALSE
2. Profile of a surface tolerance is a 2-dimensional control. FALSE
3. Profile of a surface tolerance should be used to control
TRUE
4. Profile of a line tolerances should be applied at MMC.
FALSE
5. Profile tolerances can be applied to features of size.
TRUE
trim edges on sheet metal parts.
6. Profile tolerances can be combined with other geometric TRUE
controls such as flatness to control a feature.
7. Profile of a line tolerances apply to an entire surface.
FALSE
8. Profile of a line controls apply to individual line elements. TRUE
9. Profile tolerances only control the location of a surface.
FALSE
10. Composite profile controls should be avoided because
FALSE
11. Profile tolerances can be applied either bilateral or
TRUE
12. Profile tolerances can be applied in both freestate and
TRUE
13. Tolerances shown in the lower segment of a composite
FALSE
they are more restrictive and very difficult to check.
unilateral to a feature.
restrained datum conditions.
profile feature control frame control the location of a
feature to the specified datums.
True Position Quiz
Answer questions #1-11 True or False
1. Positional tolerances are applied to individual or patterns TRUE
of features of size.
2. Cylindrical tolerance zones more closely represent the
TRUE
functional requirements of a pattern of clearance holes.
3. True position tolerance values are used to calculate the
TRUE
4. True position tolerances can control a feature’s size.
FALSE
5. Positional tolerances are applied on an MMC, LMC, or
TRUE
6. Composite true position tolerances should be avoided
FALSE
7. Composite true position tolerances can only be applied
TRUE
8. The tolerance value shown in the upper segment of a
TRUE
9. The tolerance value shown in the lower segment of a
FALSE
10. Positional tolerances can be used to control circularity
FALSE
TRUE
minimum size of a feature required for assembly.
RFS basis.
because it is overly restrictive and difficult to check.
to patterns of related features.
composite true position feature control frame applies
to the location of a pattern of features to the specified
datums.
composite true position feature control frame applies
to the location of a pattern of features to the specified
datums.
11. True position tolerances can be used to control center
distance relationships between features of size.
True Position Quiz
Questions #1-9 Fill in blanks (choose from below)
1. Positional tolerance zones can be rectangular, cylindrical,
or spherical
2. Basic dimensions are used to establish the true (theoretically
exact) position of a feature from specified datums.
3. Positional tolerancing is a 3-dimensional control.
4. Positional tolerance can apply to the axis or surface boundary
of a feature.
5. Fixed and floating fastener equations are used to determine
appropriate clearance hole sizes for mating details
6. Projected tolerance zones are recommended to prevent fastener
interference in mating details.
7. The tolerance shown in the upper segment of a composite true
position feature control frame is called the pattern-locating
tolerance zone.
8. The tolerance shown in the lower segment of a composite true
position feature control frame is called the feature-relating
tolerance zone.
9. Functional gaging principles can be applied when maximum
material condition is specified
surface boundary
floating
feature-relating
pattern-locating
rectangular
cylindrical
3-dimensional
basic dimensions
projected
location
maximum material
fixed
axis
E
N
D
Notes
Notes
Notes
Extreme Variations of Form
Allowed By Size Tolerance
25
(MMC)
25.1
25
25
24.9
25.1
(LMC)
25
(MMC)
24.9
(LMC)
25.1
(LMC)
25
(MMC)
24.9
(LMC)
MMC Perfect
Form Boundary
25.1
(LMC)
24.9
(LMC)
25
(MMC)
Virtual and
Resultant
Condition
Boundaries
Internal and External
Features (MMC Concept)
Virtual Condition Boundary
Internal Feature (MMC Concept)
14 +/- 0.5
1M A B C
A
C
XX.X
B
XX.X
As Shown on Drawing
(
Virtual Condition
Inner Boundary
Maximum Inscribed
Diameter
1 Positional
Tolerance Zone at
MMC
)
True (Basic)
Position of Hole
Other Possible
Extreme Locations
Boundary of MMC Hole
Shown at Extreme Limit
True (Basic)
Position of Hole
Calculating Virtual Condition
13.5
1
MMC Size of Feature
Applicable Geometric Tolerance
12.5
Virtual Condition Boundary
Axis Location of
MMC Hole Shown
at Extreme Limit
Resultant Condition Boundary
Internal Feature (MMC Concept)
14 +/- 0.5
1M A B C
A
C
XX.X
B
XX.X
As Shown on Drawing
(
Resultant Condition
Outer Boundary
Minimum Circumscribed
Diameter
2 Positional
Tolerance Zone at
LMC
)
True (Basic)
Position of Hole
Other Possible
Extreme Locations
Boundary of LMC Hole
Shown at Extreme Limit
True (Basic)
Position of Hole
Calculating Resultant Condition (Internal Feature)
14.5
2
LMC Size of Feature
Geometric Tolerance (at LMC)
16.5
Resultant Condition Boundary
Axis Location of
LMC Hole Shown
at Extreme Limit
Virtual Condition Boundary
External Feature (MMC Concept)
14 +/- 0.5
1M A B C
A
C
XX.XX
B
XX.X
As Shown on Drawing
(
Virtual Condition
Outer Boundary
Minimum Circumscribed
Diameter
1 Positional
Tolerance Zone at
MMC
)
True (Basic)
Position of Feature
Other Possible
Extreme Locations
Boundary of MMC Feature
Shown at Extreme Limit
True (Basic)
Position of Feature
Calculating Virtual Condition
14.5
1
MMC Size of Feature
Applicable Geometric Tolerance
15.5
Virtual Condition Boundary
Axis Location of
MMC Feature Shown
at Extreme Limit
Resultant Condition Boundary
External Feature (MMC Concept)
14 +/- 0.5
1M A B C
A
C
XX.X
B
XX.X
As Shown on Drawing
(
Resultant Condition
Inner Boundary
Maximum Inscribed
Diameter
2 Positional
Tolerance Zone at
LMC
)
True (Basic)
Position of Feature
Other Possible
Extreme Locations
Boundary of LMC feature
Shown at Extreme Limit
True (Basic)
Position of Feature
Axis Location of
LMC Feature Shown
at Extreme Limit
Calculating Resultant Condition (External Feature)
13.5
2
LMC Size of Feature
Geometric Tolerance (at LMC)
11.5
Resultant Condition Boundary
• 3X 5.0  5mm is 3 times repeated. A space is used after X
Maximum Material Condition (MMC):
The condition where the feature contains the maximum material
within the stated limits of size – for example, the largest pin or the
smallest hole.
Least Material Condition (LMC):
The condition where the feature contains the least material with in
the stated limits of size - for example, the smallest pin or largest
hole.
GEOMETRIC CHARACTERISTIC SYMBOLS
TYPE OF
TOLERANCE
CHARACTERISTIC
STRAIGHNESS
FOR
INDIVIDUAL
FEATURES
FORM
FLATNESS
CIRCULARITY
(ROUNDNESS)
CYLINDRICITY
FOR
INDIVIDUAL
OR RELATED
FEATURES
FROFILE
PROFILE OF A
SURFACE
PROFILE OF A
LINE
ANGULARITY
ORIENTATION
PERPENDICULARITY
PARALLELISM
FOR
RELATED
FEATURES
POSITION
CONCENTRICITY
LOCATION
SYMMETRY
RUNOUT
CIRCULAR
RUNOUT
TOTAL RUNOUT
SYMBOL